Drilling mast with movable and fixed unscrewing vice

ABSTRACT

The invention is a new drill for making micropiles, equipped with a mast on which the head-carrying trolley slides and having at the bottom of the mast two pairs of vices, a lower fixed vice and a upper unscrewing vice. Besides being able to rotate around the drilling axis, the unscrewing vice is able to move along said mast with respect to the lower fixed vice. The advantages are considerable, since it is no longer necessary to dismantle the rod and the covering during the extraction stages.

RELATED U.S. APPLICATIONS

[0001] Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

REFERENCE TO MICROFICHE APPENDIX

[0003] Not applicable.

FIELD OF THE INVENTION

[0004] The present patent concerns drills for making steel and/orreinforced concrete micropiles and in particular it concerns a new drillwith a translating extractor trolley for the drilling rod and therestraining covering.

BACKGROUND OF THE INVENTION

[0005] To consolidate the soil, or to make foundation piles nearstructures, or to make anchoring tie rods, and in other similar cases,micropiles are used which are made of steel or of concrete cast in holesmade in the ground with suitable equipment.

[0006] Making micropiles by casting concrete into the groundcontemplates the drilling of the ground with a drilling rod accompaniedby a cylindrical covering.

[0007] At the end of the drilling rod there is a tool driven by air orby water under pressure.

[0008] The outer covering holds back the soil around the hole until themoment of the casting and allows the extraction of the material removedby the tool of the drilling rod during the drilling operation.

[0009] The drilling rod and the outer covering are driven into the soilsimultaneously. At the end of the drilling operation the drilling rod isextracted, the pile or reinforcement and the concrete are introduced inthe covering which is extracted gradually so as to allow the concrete tobe perfectly compacted in the hole left by the covering.

[0010] Both the drilling rod and the covering are composed of variousmodular elements which are joined together, usually by screwing, untilthe necessary drilling length is obtained.

[0011] To make micropiles by casting concrete into the ground with a rodand covering, drills are used that are equipped with a mast (or guide orslide) that may be turned in various directions, on which a trolley witha drilling head slides, the drilling rod and/or the covering beingapplied on said trolley.

[0012] At the bottom end of the mast there is a group of vicescomprising two pairs of jaws, called bottom vice and top vice, thelatter being also called unscrewing vice, overlapping each other andconcentric with the path of the trolley, the drilling rod and thecovering.

[0013] In particular, the top pair of jaws rotates with respect to themast. In this way the bottom jaws hold the rod or the covering alreadyinserted while the rotating top jaws release the rod and/or coveringelements next to them.

[0014] These drills permit the creation of holes for micropiles with adrilling rod and covering, but they present a series of inconvenientaspects.

[0015] The extraction of the drilling rod and of the covering isentrusted to the head-carrying trolley, which consequently must resisthigh stress. The advance movement of the head-carrying trolley isensured by jacks, cables, chains, etc.

[0016] The screwing and unscrewing of the modular elements of thedrilling rod and of the covering are possible only when the joiningpoint is exactly between the two vices or pairs of jaws, where it isdifficult for the operator to determine, both during drilling and duringextraction the exact point in which to stop the trolley so that thejoining point is exactly between said two vices.

[0017] At present for the standard version it is necessary to perform insequence the operations described below for each element:

[0018] 1. extract the rod for one module (˜1.5 m) checking that thejoining point is between the two sets of jaws;

[0019] 2. block both vices and turn the upper unscrewing device;

[0020] 3. disengage the unscrewing device, rotate the module by turningthe head;

[0021] 4. engage the unscrewing device on the module and disengage thehead at the top;

[0022] 5. unscrew the rod from the head and put away the rod;

[0023] 6. move the head downwards until it screws onto the stillsemi-fixed module.

[0024] All these operations must obviously be repeated until thedrilling device (rod) is completely extracted.

[0025] Moreover, these operations must also be performed for thecovering.

[0026] The studies, stratagems and solutions adopted until now have notled to any acceptable result, sometimes even aggravating the situation.

BRIEF SUMMARY OF THE INVENTION

[0027] To overcome all the inconveniences described above a new type ofdrill has been designed and implemented for making micropiles withrelative shifting of the unscrewing vice with respect to the bottomvice.

[0028] The aim of the new drill is to provide a mechanism for extractingthe drilling rod and the covering that is independent of the mechanismfor the advance of the head-carrying trolley.

[0029] The characteristics of the new drill will be better explained byfollowing description with reference to the drawings enclosed as anexample without limitation, wherein:

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0030]FIG. 1 is a side view of the new drill.

[0031]FIG. 2 shows a section of the mast (R).

[0032]FIG. 3

DETAILED DESCRIPTION OF THE INVENTION

[0033] The new drill comprises a carriage (A), a motor assembly (M),multi-jointed arms (B), a mast (R), two vices (G1, G2), a trolley (C)with drilling head (T).

[0034] The carriage positions and transfers the new machine from/to thepoint of drilling and onto the transport trailer.

[0035] The motor assembly (M) generates the energy necessary for theoperation of the whole drill.

[0036] The multi-jointed arms (B) are hinged together, onto the chassisof the drill and onto the mast (R) and they direct and position saidmast (R) on the point of drilling.

[0037] The mast (R) supports the drilling trolley (C) and, at the bottomend, the two pairs of vices (G1, G2).

[0038] The two pairs of vices (G1, G2) at the end of the mast (R)overlap and are situated at the sides of the path of the trolley, of thedrilling rod and of the covering.

[0039] In particular the lower vices (G1) perform the only closing andopening movement on the drilling rod and on the covering. The higherunscrewing vices (G2) rotate around the drilling axis and are movedalong the mast (R) with respect to the lower vices (G1).

[0040]FIG. 2 shows a section of the mast (R) illustrating the movementof said upper vice (G2) with respect to the lower vice (G1).

[0041] The vice (G2) is mounted on a trolley of its own (G2 s), whichalso slides on the mast (R) and is fixed to a pair of cables (G2 v).

[0042] Said cables (G2 v) are looped around two pairs of pulleys (G2 p)and are connected to a hydraulic jack (G2 m) parallel to the axis ofsaid mast (R) and inside it. The new drill constituted as describedabove offers considerable advantages.

[0043] The extraction of the drilling rod and/or of the covering isentrusted to the second vice (G2).

[0044] The second vice (G2) grips the drilling rod or the covering andis rotated and moved upwards, taking it away from the first vice (G1).

[0045]FIG. 3 shows the same mast (3) with the vice (G1) applied thereto.

[0046] This solution is particularly advantageous because the mobileupper vice is conceived to all effects as an extractor for both the rodand the covering.

[0047] As a result it is possible, for example, to extract the rodcompletely with the head and, while said rod remains on the (drilling)axis, to extract the covering with the upper vice (G2), reinserting therod in it.

[0048] The advantages may be easily recognized, since with this systemit is possible to proceed to make the next micropile without having todismantle (unscrew and rescrew) the rod assembly or the covering.

[0049] Therefore, with reference to the above description and toenclosed drawings, the following claims are put forth.

We claim:
 1. Drill for making micropiles, equipped with a mast on whichthe head-carrying trolley slides and having at the bottom of the masttwo pairs of vices, a lower fixed vice and an upper unscrewing vice,characterised in that the unscrewing vice, besides being able to rotatearound the drilling axis, is able to move along said mast with respectto the lower fixed vice.
 2. Drill according to claim 1, characterised inthat the upper vice moves along the mast by means of its own slidingtrolley fixed to one or more chains and/or parallel cables looped aroundpairs of pulleys, and wherein said two cables are connected to ahydraulic jack.